Baryte processing -> fixing, soaking, clays etc.

aXL · 2004-06-15T15:55:03+00:00

Moin, Kollegen. Einige Beiträge im Internet, die ich in den letzten Wochen gelesen habe, legen mir nahe, meine bisherige Arbeitsweise beim Barytbelichten zu...

aXL

Hi, everyone. A few posts I’ve read online over the last few weeks have made me think I should change the way I’ve been working with baryta paper. The main problem: Baryta paper must be rinsed immediately after fixing, otherwise the thiosulphates become embedded in the paper’s felt and are impossible to remove. I haven’t paid enough attention to this so far. :o It’s much easier to pre-rinse the prints briefly, set them aside, and leave the final wash until the end of the lab session. So now I have to think about how to incorporate the washing into a sensible workflow. My main question, though, is: how do I fit the toning in there? (I haven’t had any experience with toning yet, but the next baryta prints I make will definitely be toned.) How do you lot do it? :D I practically always work with a mate in the darkroom when handling baryta. One of us handles the negatives, the other bathes the paper (wearing gloves on their fingers). But what does the process look like now: - Load the negative, remove dust - Exposure - Development 5 minutes - Stop bath for 1 minute (or a water bath?) - First fixing for 2 minutes - Second fixing for 2 minutes Meanwhile, the darkroom assistant prepares the next negative - Intermediate rinsing - Selenium toner (Shouldn’t this be done in daylight?) - Final wash according to A. Adams or Ilford (8 x 1.5 minutes) - Pre-drying That’s no problem if only a single print is to be processed. However, I have to put in a fair bit of effort to get the darkroom up and running, and I also need to find a time to meet up with my mate. Which means: I want to do a batch when a darkroom session is on the cards! :) It would be a luxury to entrust a third lab assistant with the washing. But then things get a bit tight in the room. A baryta washer would be nice, of course, but in 50x60 format it’s unaffordable and hardly practical to set up. Besides, I prefer the static washing to the constant flushing of the paper (“the dissolution of thiosulphates is an osmotic process”). Of course, I can’t get an entire exhibition run of prints done in a single night, but I’d certainly like to manage more than five prints in four hours. :( Another problem: development has to take place in the dark, whereas rinsing and, above all, toning should ideally be done in the light. Or is it feasible to carry out toning with a fixed processing time in the dark as well? What about ventilation in the darkroom? Unfortunately, I don’t have a Duka airlock that allows you to pop out of the room without the darkness ‘flowing out’. Or do you do it so that the papers are given a final rinse after development and the toning takes place on one of the following days? Do you separate the two steps and accept that you have to rinse twice? With multiple toning, there’s probably no other way. :huh: I’m absolutely curious to know what solutions you’ve found for yourselves... Thanks in advance, Axel

Gast

Hello! Yes, I do separate the two steps – I collect the prints after they’ve been soaked and dried, and then do a toning session in daylight when I get the chance. Roman

Urnes

Hi axl, Well, I keep these two steps separate. Depending on the toner you use, you really should do this by eye. Most toners alter the contrast in one direction or another, and of course you need to take that into account beforehand when making the print. What’s more, selenium toner is a nightmare if there isn’t enough ventilation, and it’s not exactly healthy. You really shouldn’t put your lab colleagues through that. As for the rinsing, I make the prints first and leave them in the water until the last one is finished, though there are usually no more than three (but then again, I don’t have anyone to help me). After that, I put them in the Washaid for 10 minutes. For the final rinse, the prints go into a sufficiently large lab tray and are rinsed for 30 minutes with the Jobo Cascade. Admittedly, I’d prefer a large flat-bed washer too, and it’s a pain every time to adjust the water flow so that there isn’t too much or too little water in the tray (it’s also a right faff balancing a 40x50 tray on the edge of a sink :D ). But it works. Regards, Sven.

MatthiasS

I also prefer static washing to constantly rinsing the paper (“the dissolution of thiosulphates is an osmotic process”).

Regarding the osmotic process: This simply means that the salt concentrations in the paper and the wash water are different, specifically lower in the water. That is why the salt has nothing better to do than to distribute itself as evenly as possible throughout its entire environment. Whether you keep the salt concentration in the bath lower than in the paper by constantly adding fresh water and draining off excess water, or whether you change the water completely, is theoretically irrelevant. On the contrary, the turbulence of the water should actually speed up the process. That’s how osmosis was once explained to me; I make no claim to accuracy – but the conclusions do at least sound logical, don’t they?

cfb_de

("The dissolution of thiosulphates is an osmotic process")

Hi everyone, that’s not correct! The correct statement would be: “The dissolution of thiosulphates is a diffusion-controlled process.” To explain: diffusion is what happens when a dissolved chemical spreads throughout a solvent until the concentration is the same everywhere. Osmosis means something else: you have two vessels with a membrane between them. In one half, the concentration is higher than in the other. And now for the key difference: in diffusion mechanisms, the dissolved substance ‘moves’; in osmosis, it is the other way round. Here, the solvent moves towards the higher concentration. Applied to the baryta print, this means that in the case of an osmotic process (though the membrane is missing here), the water from the wetting tray would move into the print, causing the print to swell and leaving less and less water in the tray. Thiosulphate would then remain entirely within the print. (Not really what we want. And certainly not what actually happens.) So, once again: diffusion. Not osmosis. Best regards, I’m just messing about today, Franz